NAME

DESCRIPTION

Parallel environments are parallel programming and runtime environments
allowing for the execution of shared memory or distributed memory
parallelized applications. Parallel environments usually require some
kind of setup to be operational before starting parallel applications.
Examples for common parallel environments are shared memory parallel
operating systems and the distributed memory environments Parallel
Virtual Machine (PVM) or Message Passing Interface (MPI).
sge_pe allows for the definition of interfaces to arbitrary parallel
environments. Once a parallel environment is defined or modified with
the -ap or -mp options to qconf(1) and linked with one or more queues
via pe_list in queue_conf(5) the environment can be requested for a job
via the -pe switch to qsub(1) together with a request of a range for
the number of parallel process to be allocated by the job. Additional
-l options may be used to specify the job requirement to further
detail.
Note, Sun Grid Engine allows backslashes (\) be used to escape newline
(\newline) characters. The backslash and the newline are replaced with
a space (" ") character before any interpretation.

FORMAT

The format of a sge_pe file is defined as follows:
pe_name
The name of the parallel environment as defined for pe_name in
sge_types(1). To be used in the qsub(1) -pe switch.
slots
The number of parallel processes being allowed to run in total under
the parallel environment concurrently. Type is number, valid values
are 0 to 9999999.
user_lists
A comma separated list of user access list names (see access_list(5)).
Each user contained in at least one of the enlisted access lists has
access to the parallel environment. If the user_lists parameter is set
to NONE (the default) any user has access being not explicitly excluded
via the xuser_lists parameter described below. If a user is contained
both in an access list enlisted in xuser_lists and user_lists the user
is denied access to the parallel environment.
xuser_lists
The xuser_lists parameter contains a comma separated list of so called
user access lists as described in access_list(5). Each user contained
in at least one of the enlisted access lists is not allowed to access
the parallel environment. If the xuser_lists parameter is set to NONE
(the default) any user has access. If a user is contained both in an
access list enlisted in xuser_lists and user_lists the user is denied
access to the parallel environment.
start_proc_args
The invocation command line of a start-up procedure for the parallel
environment. The start-up procedure is invoked by sge_shepherd(8) prior
to executing the job script. Its purpose is to setup the parallel
environment correspondingly to its needs. An optional prefix "user@"
specifies the user under which this procedure is to be started. The
standard output of the start-up procedure is redirected to the file
REQNAME.poJID in the job’s working directory (see qsub(1)), with
REQNAME being the name of the job as displayed by qstat(1) and JID
being the job’s identification number. Likewise, the standard error
output is redirected to REQNAME.peJID
The following special variables being expanded at runtime can be used
(besides any other strings which have to be interpreted by the start
and stop procedures) to constitute a command line:
$pe_hostfile
The pathname of a file containing a detailed description of the
layout of the parallel environment to be setup by the start-up
procedure. Each line of the file refers to a host on which
parallel processes are to be run. The first entry of each line
denotes the hostname, the second entry the number of parallel
processes to be run on the host, the third entry the name of the
queue, and the fourth entry a processor range to be used in case
of a multiprocessor machine.
$host The name of the host on which the start-up or stop procedures
are started.
$job_owner
The user name of the job owner.
$job_id
Sun Grid Engine’s unique job identification number.
$job_name
The name of the job.
$pe The name of the parallel environment in use.
$pe_slots
Number of slots granted for the job.
$processors
The processors string as contained in the queue configuration
(see queue_conf(5)) of the master queue (the queue in which the
start-up and stop procedures are started).
$queue The cluster queue of the master queue instance.
stop_proc_args
The invocation command line of a shutdown procedure for the parallel
environment. The shutdown procedure is invoked by sge_shepherd(8) after
the job script has finished. Its purpose is to stop the parallel
environment and to remove it from all participating systems. An
optional prefix "user@" specifies the user under which this procedure
is to be started. The standard output of the stop procedure is also
redirected to the file REQNAME.poJID in the job’s working directory
(see qsub(1)), with REQNAME being the name of the job as displayed by
qstat(1) and JID being the job’s identification number. Likewise, the
standard error output is redirected to REQNAME.peJID
The same special variables as for start_proc_args can be used to
constitute a command line.
allocation_rule
The allocation rule is interpreted by the scheduler thread and helps
the scheduler to decide how to distribute parallel processes among the
available machines. If, for instance, a parallel environment is built
for shared memory applications only, all parallel processes have to be
assigned to a single machine, no matter how much suitable machines are
available. If, however, the parallel environment follows the
distributed memory paradigm, an even distribution of processes among
machines may be favorable.
The current version of the scheduler only understands the following
allocation rules:
<int>: An integer number fixing the number of processes per host. If
the number is 1, all processes have to reside on different
hosts. If the special denominator $pe_slots is used, the full
range of processes as specified with the qsub(1) -pe switch
has to be allocated on a single host (no matter which value
belonging to the range is finally chosen for the job to be
allocated).
$fill_up: Starting from the best suitable host/queue, all available
slots are allocated. Further hosts and queues are "filled up"
as long as a job still requires slots for parallel tasks.
$round_robin:
From all suitable hosts a single slot is allocated until all
tasks requested by the parallel job are dispatched. If more
tasks are requested than suitable hosts are found, allocation
starts again from the first host. The allocation scheme
walks through suitable hosts in a best-suitable-first order.
control_slaves
This parameter can be set to TRUE or FALSE (the default). It indicates
whether Sun Grid Engine is the creator of the slave tasks of a parallel
application via sge_execd(8) and sge_shepherd(8) and thus has full
control over all processes in a parallel application, which enables
capabilities such as resource limitation and correct accounting.
However, to gain control over the slave tasks of a parallel
application, a sophisticated PE interface is required, which works
closely together with Sun Grid Engine facilities. Such PE interfaces
are available through your local Sun Grid Engine support office.
Please set the control_slaves parameter to false for all other PE
interfaces.
job_is_first_task
This parameter is only checked if control_slaves (see above) is set to
TRUE and thus Sun Grid Engine is the creator of the slave tasks of a
parallel application via sge_execd(8) and sge_shepherd(8). In this
case, a sophisticated PE interface is required closely coupling the
parallel environment and Sun Grid Engine. The documentation
accompanying such PE interfaces will recommend the setting for
job_is_first_task.
The job_is_first_task parameter can be set to TRUE or FALSE. A value of
TRUE indicates that the Sun Grid Engine job script already contains one
of the tasks of the parallel application, while a value of FALSE
indicates that the job script (and its child processes) is not part of
the parallel program.
urgency_slots
For pending jobs with a slot range PE request the number of slots is
not determined. This setting specifies the method to be used by Sun
Grid Engine to assess the number of slots such jobs might finally get.
The assumed slot allocation has a meaning when determining the
resource-request-based priority contribution for numeric resources as
described in sge_priority(5) and is displayed when qstat(1) is run
without -gt option.
The following methods are supported:
<int>: The specified integer number is directly used as prospective
slot amount.
min: The slot range minimum is used as prospective slot amount. If
no lower bound is specified with the range 1 is assumed.
max: The of the slot range maximum is used as prospective slot
amount. If no upper bound is specified with the range the
absolute maximum possible due to the PE’s slots setting is
assumed.
avg: The average of all numbers occurring within the job’s PE
range request is assumed.
accounting_summary
This parameter is only checked if control_slaves (see above) is set to
TRUE and thus Sun Grid Engine is the creator of the slave tasks of a
parallel application via sge_execd(8) and sge_shepherd(8). In this
case, accounting information is available for every single slave task
started by Sun Grid Engine.
The accounting_summary parameter can be set to TRUE or FALSE. A value
of TRUE indicates that only a single accounting record is written to
the accounting(5) file, containing the accounting summary of the whole
job including all slave tasks, while a value of FALSE indicates an
individual accounting(5) record is written for every slave task, as
well as for the master task.

RESTRICTIONS

Note, that the functionality of the start-up, shutdown and signaling
procedures remains the full responsibility of the administrator
configuring the parallel environment. Sun Grid Engine will just invoke
these procedures and evaluate their exit status. If the procedures do
not perform their tasks properly or if the parallel environment or the
parallel application behave unexpectedly, Sun Grid Engine has no means
to detect this.